Apparatus for manufacturing helically finned tubes



May 14, 1957 R. c. EDWARDS APPARATUS FOR MANUFACTURING HELICALLY FINNEDTUBES Filed July 24, 1953 IN VEN TOR.

RAY QEDWARDS A w El APPARATUS FOR MANUFACTURING HELICALLY FINNED TUBESRay C. Edwards, Pompton Plains, N J.

Application July 24, 1953, Serial No. 370,041

1 Claim. (Cl. 153-645) This invention relates to apparatus formanufacturing helically finned tubes by winding upon a tube a finformingmetal ribbon. In convector heating systems and analogous heat transfersystems, in order to obtain maximum heat transfer from the heating tubesto the area to be heated, it is desirable to provide within the limitsof said conductivity maximum heat radiation surfaces on the finned tubesemployed for conveying the heating medium. However, with tube finningapparatus heretofore available it has been impossible to reach thisdesirable goal due to the fact that only limited width of metal ribboncould be wound and effectively maintained upon the tube due to itsflexibility and thickness of the ribbon and the inability to sturdilymaintain relatively wide metal ribbon during the winding operation.

The present invention provides apparatus whereby fins having a widthapproximately one-third greater than the diameter of the tube may bewound on a tube and effectively maintain in position against buckling,undesirable twisting, etc., during the winding operation and whereby allfins will be accurately maintained in position during and after windingupon a tube, thus providing finned tubes having greatly increasedradiation surface over finned tubes heretofore available.

The present invention is an improvement upon the apparatus formanufacturing helically finned tubes disclosed in my prior Pat. No.2,635,571, issued April 21, 1953, whereby the apparatus of that patentembodying the improvement of the present invention may be employed tomanufacture finned tubing having greatly increased radiation surfaceover finned tubes manufactured by the apparatus without the improvementand by other known apparatus for such manufacture.

With these and other objects in view, as may appear from theaccompanying specification, the invention consists of Various featuresof construction and combination of parts, which will be first describedin connection with the accompanying drawings, showing apparatus formanufacturing helically finned tubes of a preferred form embodying theinvention, and the features forming the invention will be specificallypointed out in the claim.

In the drawings:

Figure 1 is a fragmentary side elevation of the finned tubemanufacturing apparatus showing the present invention applied thereto.

Figure 2 is an end view of the structure shown in Figure 1.

Figure 3 is a fragmentary section through the apparatus taken on theline 3-3 of Figure 1.

Figure 4 is a longitudinal section through the apparatus shown in Figure1 and taken on the line 4-4 of Figure 2.

Since the present invention relates specifically to the mechanism of theapparatus for manufacturing helically finned tubes disclosed in my priorPat. No. 2,635,571, issued April 21, 1953, which relates to the windingof the crimped helical fin of a helically finned forming ribbon upon thetube and the ironing out of the crimps on the nited States Patent outerperimetrical portions of such fins the entire mechanism formanufacturing the tubes is not illustrated in the drawings and will notbe described herein, it being understood that the metal ribbon crimpingmechanism, driving mechanisms to provide rotation of the elementsinvolved in the present invention, the bonding mechanism, etc, may inthe present invention be that either employed in the said Letters Patentor any other suitable mechanism to provide the functions.

in the present invention, like in my prior patent the metal tube 1 uponwhich the thin metal ribbon indicated at 2, which has been previouslycrimped crosswise throughout its entire width, is helically wound toprovide radiating fins on the tube which passed through the fin windingand ironing head structure 3. As described and shown in my prior PatentNo. 2,635,571, the fin winding and ironing head 3' embodies means forrotating the tube 1 and advancing it longitudinally through the head 3as the metal ribbon is wound thereon. The fin forming metal ribbon 2,which as stated above has been previously crimped in laterally extendingsubstantially parallel crimps throughout its entire width is guided bysuitable means (not shown) to the head 3 where it is engaged between, inthe present instance, a pair of ironing rollers 5 and an anvil 6. Theanvil 6 is rotated by a hollow shaft 6 on which is mounted the sheave 4'of the power transmitting mechanism 4, and is provided with an axialbore through which the tube 1 projects. The outer fin engaging face 7 ofthe anvil 6 is recessed for a predetermined distance outwardly of itsaxis as shown at 8 so that the portion of the metal ribbon 2 whichdirectly passes this recessed portion will not have the crimps ironedtherefrom. Thus, the inner edge portions of the fins indicated at 9 willprovide crimped edgewise engagement with the tube 1 to facilitate thestabilization of the fins in their contact with the tube.

The present invention is provided for permitting the winding of fins ofrelatively great width on the tube with the respective fins which havepreviously been wound upon tubes to provide finned heat transfer tubes.The finned tubes of the present invention are particularly ofadvantageous use in convection heating systems wherein a heating fluidsuch as hot water or steam is circulated through the tubes to heat theambient atmosphere such as in the heating of homes, rooms or otherenclosures where the fins themselves are not subjected to flow of fluidstresses and where it is particularly desirable to provide a maximumheat transfer surface and the metal ribbon employed for forming the finsin the present application has a width approximately one-third greaterthan the diameter of the tube.

With all of the known types of apparatus for winding metal fin formingribbon helically upon a tube and in edgewise engagement therewith it isimpossible to wind such wide tubes and effectively maintain the tube inposition against buckling, undesirable twisting, etc., during theWinding and crimp ironing operation. The present invention provides amechanism performing this operation by the employment of two ironingrollers 5 and 5a, the axes of which are disposed substantially at anglesof to each other and at angles of 45 with respect to a vertical planebisecting the axis of the tube 1. The axes of rotation of the twoironing heads 5' and 5a are inclined at acute angles to the axis of thetube 1 and converge towards the axis of the tube 1 as clearly shown inFigures 1 and 2 of the drawings. The ironing rollers 5' and 5a arecarried by stub shafts 11 which are rotatably supported by suitablebearings 12 on the head 3. The shafts 11 are rotated by means of gears13 which mesh with a gear 14 carried by the block 3. The shafts 11 arespring tensioned by means of springs 15 to urge the inner angled metalribbon ironing surfaces 16 of the ironing rollers 5 and 5a towards theironing face 7 of the anvil 6 and so as to press the metal ribbon 2against the ironing face of the anvil 6 to iron out the crimps on theouter portions of the fins 9 as they are wound upon the tube. Due to thewidth of the metal ribbon it has a tendency to buckle or twist duringthis ironing and winding operation and to prevent such twisting andbuckling of the ribbon and to insure the proper ironing out of thecrimps in the outer portions of the fins a fin retarding finger 20 isprovided which is attached to the head 3 by means of an attachingbracket 21. The retarding finger 20 is in the form of a fiat piece ofmetal comprising the attaching portion 23 and the curved finger 24 whichhas an inner concave edge curved to conform to the curvature of theouter surface of the tube 1 is clearly shown in Figure 2 of thedrawings. The finger 20 extends parallel to the ironing face 7 of theanvil 6 and engages the surface of the metal ribbon as it is being woundupon the tube opposite to the surface which is engaged by the anvil 6.The retarding finger 20 serves the dual function of staying andstabilizing the inner portion of the fin during the winding and ironingoperation and serves to retard the advancement of the fin until it hasbeen engaged by both of the ironing rollers 5' and 5a, thus preventingany buckling or twisting of the fin during the interim between itsengagement by the two ironing rollers. The fin engaging side of thefinger 20 is also parallel to the successive ribbon engaging portions ofthe angled ribbon ironing surfaces 16 of the ironing rollers as isclearly shown in Figure 4 of the drawings.

It will be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown, but that they maybe widely modified within the invention defined by the claim.

What is claimed is:

Apparatus for manufacturing helically finned tubes embodying means forrotating a tube and means for winding a laterally crimped fin formingmetal ribbon helically about a tube in edgewise engagement therewithincluding a fin winding and ironing head embodying a frame, an ironinganvil carried by said head and provided with an opening through whichthe tube passes, a pair of ironing rollers rotatably carried by saidhead and arranged in spaced relation to engage the crimped metal ribbonin sequence and cooperating with said anvil to iron out the crimps inthe outer edge portion of the metal ribbon as it is wound on the tube,means for rotating said ironing rollers, said anvil having a portion ofits metal ribbon engaging face recessed to prevent ironing out of thecrimps in the metal ribbon near to its tube engaging edge, and aretarding finger curved to substantially conform to the curvature of thecircumference of the tube carried by said frame and held stationaryrelative to the rotation of said ironing rollers, said finger positionedto engage said metal ribbon near its inner tube engaging edge and on theface of the ribbon which is opposite to the recessed portion of saidanvil and which is traveling between said pair of ironing rollers toretard the advancement of the fins until the fins forming ribbon hasbeen rolled against the anvil by both of said ironing rollers.

References Cited in the file of this patent UNITED STATES PATENTS

